Switched Capacitor Integrator With Level-Shifting Capacitor
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Solution Overview
Problem
Conventional integrator circuits face challenges in achieving low power consumption while maintaining a wide dynamic range and minimizing noise, particularly due to limitations in supply voltage and thermal noise associated with amplifiers, which can be exacerbated by the need for higher input voltage potentials from external sensors.
Innovation Solution
The proposed solution involves an integrator configuration that includes a level-shifting capacitor, a feedback capacitor, a switch module, a pre-amplifier stage, and a multi-path amplifier module, allowing for reduced supply voltage to the pre-amplifier stage while maintaining a higher input voltage for the multi-path amplifier, thereby balancing power consumption and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the supply voltage to the amplifier is reduced to lower power consumption, then power consumption is reduced, but the dynamic range and input common mode range are limited
Solution Approach 1:
The amplifier is divided into two separate amplifiers: a first amplifier with low supply voltage for low power consumption and low noise, and a second amplifier with high supply voltage for wide input common mode range. This segmentation allows each amplifier to be optimized for its specific function without compromise.
Solution Approach 2:
A level-shifting capacitor is introduced as an intermediary element between the first and second amplifiers. This capacitor couples the output of the first amplifier to the input of the second amplifier while providing DC level shifting, enabling the second amplifier to handle high input voltages while the first amplifier operates at low voltage.
2Reliability
If the feedback capacitor is increased to handle higher input currents with low supply voltage, then the integrator can accept higher input currents, but the integrator gain becomes lower and the output signal may be too small to be detected
Solution Approach 1:
The patent employs a feedback capacitor that is coupled to the input of the first amplifier through the level-shifting capacitor. This feedback mechanism allows the integrator to handle high input currents while maintaining appropriate gain, as the feedback path is established through the capacitor network rather than directly across the low-voltage amplifier.
3Object-affected harmful factors
If the supply current is increased to reduce thermal noise, then thermal noise is reduced, but power consumption increases
Solution Approach 1:
The amplifier function is segmented between two amplifiers with different power characteristics. The first amplifier operates at low supply voltage and consumes low power, while the second amplifier operates at high supply voltage. This segmentation allows the system to achieve low noise performance without requiring high power consumption in the low-voltage path.
Solution Approach 2:
Different parts of the signal path are given different quality characteristics: the first amplifier stage is optimized for low noise with appropriate biasing, while the second amplifier stage is optimized for handling high input voltages. Each stage has locally optimized parameters suitable for its specific function in the signal chain.
Data Source
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AI summary
An integrator is described that may include a level-shifting capacitor, a feedback capacitor, a pre-amplifier stage and a multi-path amplifier module. The integrator may have inputs for connected an input signal source to the level-shifting capacitor. The level-shifting capacitor is connected to an input of a pre-amplifier stage of an integration signal path and to the input. The level-shifting capacitor may level shift the voltage at the input of the circuit to a lower voltage at the input of the pre-amplifier stage. Thereby, the supply voltage to the pre-amplifier stage may be reduced as well as have limited power consumption, limited temperature rise, and reduced noise that may be attributed to any thermal effects.